1. Field of the Invention
This invention is in the field of interface apparatus and method for an electronic system, such as a home or office automation system, home security system, or video surveillance or monitoring system. More particularly, the present invention relates to such an interface for such a home or office electronic system which is aesthetically pleasing, is concealed, and which provides for user interface with the system through an interface apparatus which to the uninformed appears to be a decorative mirror, and which does not appear to be a surveillance display, a security system interface, an automation interface, or a communication or interface device of any kind.
2. Related Technology
As more and more homes incorporate more and higher levels of technology a new requirement has emerged. That is, more and more houses are incorporating home automation and visual surveillance systems. But, the current state of the art in user interface devices and methods for these home automation and visual surveillance systems provide, for example, a wall-mounted keypad and annuciator apparatus. For visual surveillance systems, either separate television monitors are provided, or the user can provide for the video images from the various security camera's to be displayed on common household televisions. Some more contemporary home security or video surveillance systems provide for the system to incorporate a touch screen display. But, the display device is nevertheless in open sight and is an apparent part of a home security or monitoring system. So, anyone who visits the home, such as delivery people, or workmen, who see the location where the monitor or display is located immediately have a good idea of the presence and nature of the home security system.
Several types of touch screen sensing technologies currently exist which are able to sense a touch on the device, i.e., on the front of a back lighted visual display, or cathode ray tube (CRT) of some type. These systems work well in their own right, except for one the one subjective, aesthetic, and practical drawback pointed out above. That is, the presence of the home security system is immediately apparent to anyone who sees the location of the display device, monitor, or interface device. The presence and some information about the nature of the security system at the home is also apparent. And finally, the home secuity system control and visual monitoring equipment may not itself be very attractive. That is, the apparatus may not be obtrusive when located in a computer room, but is certainly not part of a living room or kitchen décor. Yet, the living room, family room, kitchen, and bedroom are where residents of a home most want to be able to interface with their home security system.
Further to that above, while many users consider the look of the touch screen display panel obtrusive, they also go to great lengths to cover or hide the units from plain site. Users often mount the units in an operationally compromised location simply because they don't want them to be seen by guests, salespeople, workmen, and visitors.
Further to the above, touchscreen displays have become more and more commonplace, especially in commercial and industrial applications, as their price has steadily dropped over the past decade. There are three basic touch screen systems that are used to recognize a person's touch:                Resistive        Capacitive        Surface acoustic wave        
The resistive touch screen system consists of a normal glass panel that is covered with a conductive and a resistive metallic layer. These two sandwiched layers are held apart by spacers, and a scratch-resistant layer is placed on top of the sandwich structure. An electrical current runs through the two layers while the monitor is operational. When a user touches the screen, the two layers make electrical contact in that exact spot. The change in the electrical field is noted and the coordinates of the point of contact are calculated by the computer. Once the coordinates are known, a special driver translates the touch into touch locations coordinates that the operating system can understand, much as a computer mouse driver translates a mouse's movements into a click or a drag.
In the capacitive touch sensing system, a layer that stores electrical charge is placed on the glass panel of the monitor or display. When a user touches the monitor with his or her finger, some of the charge is transferred to the user, so the charge on the capacitive layer decreases. This decrease is measured in circuits located at each corner of the monitor. The computer calculates, from the relative differences in charge at each corner, exactly where the touch event took place and then relays that information to the touchscreen driver software. One advantage that the capacitive system has over the resistive system is that it transmits almost 90 percent of the light from the monitor, whereas the resistive system only transmits about 75 percent. This gives the capacitive system a much brighter and clearer picture than the resistive system.
On the monitor or display of a surface acoustic wave system, two transducers (one receiving and one sending) are placed along the x and y axes of the monitor's glass plate. Also placed on the glass are reflectors—they reflect an electrical signal sent from one transducer to the other. The receiving transducer is able to tell if the wave has been disturbed by a touch event at any instant, and can locate it accordingly. The wave setup has no metallic layers on the screen, allowing for 100-percent light throughput and perfect image clarity. This makes the surface acoustic wave system best for displaying detailed graphics (both other systems have significant degradation in clarity).
Another area in which the systems differ is in which stimuli will register as a touch event. A resistive system registers a touch as long as the two layers make contact, which means that it doesn't matter if a user touches it with a finger, a pen, a stylus, or any other object. A capacitive system, on the other hand, must have a conductive input, usually the user's finger, in order to register a touch. The surface acoustic wave system works much like the resistive system, allowing a touch with almost any object—except small objects like a pen tip, which do not have sufficient cross sectional area to make a measurable change in the wave pattern.
As far as price is concerned, the resistive touch screen system is the cheapest; its clarity is the lowest of the three, and its layers can be damaged by sharp objects. The surface acoustic wave system is usually the most expensive.
Further to the above, just about everyone has seen a television show or movie in which a criminal suspect is questioned while detectives watch from behind a one-way mirror. Many people don't understand how a piece of glass manages to reflect light from one side while remaining clear on the other? The secret is that it doesn't remain clear on the other side. A one-way mirror has a reflective coating applied in a very thin, sparse layer—so thin that it's called a half-silvered surface. The name half-silvered derives from the fact that the reflective molecules (which may not be silver in color) coat the glass so sparsely that only about half the molecules needed to make the glass an opaque mirror are applied. Thus, at the molecular level, there are reflective molecules speckled all over the glass in an even or patterned film, but only half the surface area of the glass is covered. The half-silvered surface will reflect about half the light that strikes its surface, while letting the other half go straight through.
So, in the television shows or movies, why doesn't the “criminal suspect” see the detectives in the next room?. The answer lies in the relative lighting levels of the two rooms. The room in which the glass looks like a mirror is kept very brightly lighted, so that there is plenty of light to reflect back from the mirror's surface. The other room, in which the glass looks like a window, is kept dark, so there is very little light to transmit through the glass. On the criminal's side, the criminal sees his own reflection. On the detectives' side, the large amount of light coming from the criminal's side is what they predominantly see. If the lights in the room with the mirror are suddenly turned out, or the lights in the observation room are suddenly turned on, then the one-way mirror becomes essentially a window, with people in each room able to see those in the other.